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When to plant Celeriac in Clinton County, IL

Plant Celeriac in Clinton County after April 10; the prime window is March 27–April 17. A second sowing from August 10 to August 24 extends the harvest into fall.

When to Plant Celeriac in Clinton County, IL

Clinton County, Illinois Zone 6b August

Top priorities for Clinton County, Illinois gardeners in August

Your garden in Clinton County, Illinois is working on a schedule, even when you're not. Here's where you should be this August.

Avg. last frost April 10
Avg. first frost October 19
Soil temp (4") 82°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Harvest celeriac as they ripen

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

  2. Sow celeriac for an autumn harvest

    Your first frost is about 10 weeks away — plenty of time for these to mature.

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Celeriac is a celery relative grown for its knobby, flavorful root rather than its stalks. It has a rich celery flavor and is excellent roasted, mashed, or in soups.

Clinton County, Illinois is in USDA Zone 6b. The average last spring frost is April 10 and the first fall frost is October 19, giving you a growing season of approximately 192 days.

At an elevation of 1,142 feet, Clinton County receives approximately 38.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Celeriac during the growing season.

Clinton County, IL (Zone 6b) Moderate season
192 days
Last Spring Frost April 10
192 growing days
First Fall Frost October 19

Clinton County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7

Drainage

Well Drained

Celeriac Planting Risk Windows

Early Start (70% safe) ✓ Fits season (52 days to spare)
Start indoors: Feb 28 Transplant: Apr 4 🍅 Harvest: Jul 18 – Aug 22
Recommended (50%) ✓ Fits season (52 days to spare)
Start indoors: Mar 6 Transplant: Apr 10 🍅 Harvest: Jul 24 – Aug 28
Safe Start (90%) ✓ Fits season (54 days to spare)
Start indoors: Mar 15 Transplant: Apr 19 🍅 Harvest: Aug 2 – Sep 6

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Clinton County

How your county's soil matches Celeriac's growing requirements.

Soil pH

Your soil pH (6.0–7.0) is within Celeriac's preferred range (6.0–7.0).

Soil Texture

The silt loam soil in Clinton County is excellent for Celeriac — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.5%) — Celeriac will thrive.

How to Plant Celeriac

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Celeriac Water Budget

Plant needs
0.9″/week
Rainfall provides
0.8″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 136 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Celeriac

Celeriac needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Celeriac Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 3.9" 3.5" 0.4" 💧 Light watering
May 3.9" 4.3" 0" ✅ Rainfall sufficient
Jun 3.9" 4.9" 0" ✅ Rainfall sufficient
Jul 3.9" 4.3" 0" ✅ Rainfall sufficient
Aug 3.9" 3.9" 0" ✅ Rainfall sufficient
Sep 3.9" 3.4" 0.5" 💧 Light watering
Oct 3.9" 3.2" 0.7" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Clinton County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Celeriac Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Celeriac needs ~1,512 GDD — county provides 2,640 GDD Excellent fit

Celeriac Planting Timeline — Clinton County, IL

Celeriac Planting Calendar

Activity When Date Range
Start Indoors March 6 Mar 6 – Mar 20
Transplant Outdoors April 10 Apr 10 – Apr 24
Direct Sow March 27 Mar 27 – Apr 17
Harvest July 24 Jul 24 – Aug 28
Fall Sowing August 10 Aug 10 – Aug 24

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May
June
July Harvest
August Fall Sowing Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · Only during dry spells

📅 Days to Maturity

100–120 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 6b

📆 Growing Season

192 days in Clinton County

Growing Tips for Celeriac in Clinton County

Direct sow Celeriac outdoors after April 10 in Clinton County when soil has warmed and frost danger has passed.

Common pests for Celeriac in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 10-12 weeks before last frost. Remove side roots as they develop to encourage a single large bulb. Harvest after a light frost for best flavor.

Companion Planting

Good Companions

Avoid Planting Near

  • Carrots
  • Parsnip

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Celeriac in Clinton County, IL?

Clinton County is in Zone 6b with an average last frost of April 10. Plan your Celeriac planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clinton County, IL?

Clinton County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 10 and first fall frost is October 19.

When should I plant Celeriac in Clinton County, IL?

In Clinton County, IL, plant Celeriac after the last frost (around April 10) and before the first frost (around October 19). Best results when soil holds above 50°F.

What growing zone is Clinton County, IL for Celeriac?

Clinton County sits in USDA Zone 6b. Celeriac grows reliably in zones 3a through 9b, so it's a good fit here.

Can Celeriac grow in Clinton County's climate?

Yes — Celeriac grows well in Clinton County's temperate climate. Clinton County averages a 192-day frost-free season, with last frost around April 10 and first frost around October 19.

🌱

Your Clinton County Garden Planner — Free

A 22-page printable planner built for Clinton County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Clinton County, IL. Local conditions may vary. Last updated: August 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.